Brake drum with cooling means



' Aug. 7, 1951 1. A. WYANT BRAKE DRUM WITH COOLING MEANS meg .Juh 5, 1947 In 22 72 for Ira .1? lflyare M ,flizarreeys.

Aug. 7, 1951 l. A. WYANT BRAKE DRUM WITH COOLING MEANS 2 Sheets-Sheet Filed June 5, 1947 Uuuuu Patented Aug. 7, 1951 UNITED STATES PATENT OFFICE 2,503,769 BRAKE DRUM wrrn COOLING MEANS Ira A. Wyant, Muskegon Heights, Mieh., assignor to Campbell, Wyant & Cannon Foundry 00., Muskegon, Mich., a corporation of Michigan Application June 5, 1947, Serial No. 752,671

3 Claims. 1

to the evaporation of six gallons of water a minute, probably about 150,000 to 250,000 B. t. u.s. Good coal, properly burned, generates about 12,000 to 15,000 E. t. u.s per pound, so the total volume of heat, while great, is not excessive. The difficulty, however, is that in connection with airplane operation, the plane traveling at a very high speed when it hits the ground must be arrested very rapidly, and this heat is generated in a very short length of time, in fractions of seconds. Under these circumstances, special means must be provided to transfer the heat rapidly to keep the brake drum from destructive overheating. Efl'orts have been made to do this by applying conducting fins to the outside ofa steel brake drum of the centrifuse type wherein cast iron brake lining is fused to the inside of the steel drum. The difliculty is that under these circumstances the heat generation is so rapid that the heat does not have time to be conducted through the cast iron and the steel, which are relatively low conductors, to the copper fins before the brake drum is dangerously overheated.

I propose to take care of this situation by bringing the highly conductive copper fins right up to the point where the heat is generated so that the delay or heat dam, or heat bottleneck, caused by the need of passing heat through the cast iron and steel will be avoided.

I propose to take the conventional steel brake drum, slot it about its periphery, and set into the slots copper heat-conducting fins, vanes or pins which extend outwardly beyond the drum and project inwardly through the periphery of the drum. I will then cast the gray iron lining on the inside of the drum in the usual way, thus imbedding the copper fins in the gray iron liner and fusing the liner to the shell and to the vanes of the conducting members or fins.

I propose to have these fins extend inwardly far enough so that they will, when the drum lining is machined, extend preferably to within .015 to .025 inch from the machined braking surface; though, under some circumstances, if copper extends clear to the braking surface no harm will be done, or if the copper terminates short of 2 the braking surface and the braking surface is removed in line with the copper fin, still no harm will be done because the brake shoe is rigid and will engage the drum without interference by the pockets at the ends of the bases of the fins, and in any one of the three cases the copper fin will be so close to the point where the heat is generated that the high heat conductivity of the copper is effective at once to dissipate the heat independent of the resistance to heat flow through the liner and shell.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a side elevation of a brake drum embodying my invention;

Figure 2 is a radial section along the line 2--2 of Figure 1;

Figure 3 is an axial section along the line 3-4 of Figure 2;

Figure 4 is a detail section similar to Figure 2, showing a modified form;

Figure 5 is a section taken on a plane perpendicular to the axis of a modified form of the drum;

Figure 6 is a section along the line 6-4 of Figure 5; and

Figure 7 is a view similar to Figure 1, showing a modified form.

Like parts are indicated by like characters in the specification and drawings.

l is a reinforcing and strength-giving shell, preferably of steel. 2 is an inwardly extending flange centrally apertured at 3, and apertured at 4 for attachment to a wheel. 5, 5 are a series of slots extending through the cylindrical portion of the shell. 6 are heat-conducting vanes or fins of any suitable heat-conducting material, preferably copper, located within the slots in the periphery of the shell and extending both inwardly and outwardly through said slots with respect to the shell. These fins have therefore, outwardly extending, air-dissipating portions 1 and inwardly extending liner-contacting bases 8. 9 is a brakeshoe-engaging lining, preferably of cast iron, fused to the inner periphery of the shell, and also fused and bonded to the portions 8 of the heatconducting vanes so that there is a close, intimate, homogeneous bond between the heat-conducting vanes and the mass of the liner, and it will be noted that these vanes extend substantially to the finished inner periphery of the liner.

In assembling my brake drum, the shell is first formed, having slots or apertures through the cylindrical portion thereof. The copper vanes.

poured intothe drum is higher than the meltin point of the copper fins. However, since the drum is rotating, and since the mass of cast iron is comparatively small, and since the time required for it to harden is short, there is only enough melting or fusing of the copper fin to provide the desired intimate homogeneous bond between the copper and the iron.

It will be noted that as originally cast, the fin erated by contact between the brake shoe and the cast iron liner, and the heat isthus drawn from the cast iron liner by the copper fins at the highest possible rate, thereby cooling the liner,

which by itself is a poor conductor.

The exact position of the inner ends of the fins with respect to the inner surface of the liner is not important. So long as the fin comes in substantially to the braking surface where the heat is generated. If the copper fin extends clear out to the brake-shoe-engaging surface, no harm is done. If it extends beyond, it will be cut away when the surface is machined. If it comes slightly short, it will still serve its purpose. But the essential thing is that the inner ends of the conducting members or fins terminate substantially at the point where the heat is generated, namely, at the brake-shoe-engaging surface of the liner.

In the modified form shown in Figure 4, instead of the short vanes or fins I, I use arc.segmental vanes ll, each fin having a plurality of feet l2 which penetrate through the slots 5 in the shell I, to be welded or fused into the liner 9 just as in the form disclosed in Figures 1, 2 and 3.

Since, in connection with the casting of the pressed fit in the shell. The contour of the fins H may be such that they can be sprung in, .or these fins may be brazedor soldered or otherwise attached. The particular method by which they are attached to the shell to hold them together so for the casting operation, however, forms no part of my present invention and so is not disclosed in the specification or drawings.

In the modified form shown in Figures 5 and 6, there is added to the modification characteristic of Figure 4 the series of shrouds II brazed or otherwise suitably fastened to the outer peripheries of a series of vanes ll. These shrouds are somewhat shorter along a peripheral line than are the vanes, and each shroud has an outwardly extending air scoop l4 and terminates in front of the rear end of the vanes, assuming that the wheel rotates in a counterclockwise direction, in the direction of the arrow, so that aircan escape from between the vanes and shroud. Thus, the air. by the scoop, as the brake drum rotates, is forced through a series of narrow passages, thus increasing the pressure of air against the heat-dissipating surfaces and improving the efficiency of heat dissipation.

In a further modified form of Figure 7, the vanes 16 are inclined in adjacent groups to the plane perpendicular to the axis. These'vanes are shown as being set into inclined slots, though, of course, slots similar .to those of Figure 3 might be usedand the vanes themselves merely threaded. Here again, the inclination of the vane results in an increasing pressure and impingement of cooling air upon the surface of the vane, thereby promoting efllciency of heat transfer.

I claim:

1. A brake drum, including a steel shell, a. cast iron liner therein, a plurality of heat-conducting vanes incontact with the liner, extending out wardly therefrom, and means associated with the vanes for forcing airunder pressure into contact with the vanes as the drum rotates.

2. A brake drum, including a steel shell, a cast iron liner therein, a plurality of heat-conducting vanes in contact with theliner, extending outwardly therefrom, and a shroud encircling a portion of the vanes, having an air scoop adapted to force air into the space between the shroud and the vanes as the wheel rotates.

3. A brake drum, including a steel shell, a castiron liner therein, a plurality of heat-conducting vanes in contact with the liner, extending outwardly therefrom and inwardly into cast relationship with the liner, each vane having a plurality of feet extending through the liner to provide such cast relationship, and a shroud associated with a plurality of said vanes on the outer periphery thereof, having an air scoop at one end and at the other end'terminating short of the ends of the vanes.

IRA A. WYANI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,473,366 Walther Nov. 6, 1923 1,881,002 Udale Oct. 4, 1932 2,008,173 Bake at al. July 16, 1935 2,026,733 Fast Jan. 7, 1936 

